1. Field of the Invention
The present disclosure relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a light weight and a thin profile with various external appearances and a method of fabricating the liquid crystal display device.
2. Discussion of the Related Art
A liquid crystal display (LCD) device that has been widely used for a television or a monitor because of its superiority in displaying a moving image and high contrast ratio produces images by using optical anisotropy and polarization properties of liquid crystal molecules. The LCD device includes a liquid crystal panel that is composed of facing two substrates and a liquid crystal layer between the two substrates. An alignment direction of liquid crystal molecules in the liquid crystal panel is changed by an electric field so that the liquid crystal panel can produce difference in transmittance.
Since the LCD device is a non-emissive type display device, an additional light source is required. Accordingly, a backlight unit including a light source is disposed under the liquid crystal panel. For example, one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL) and a light emitting diode (LED) may be used as the light source.
FIG. 1 is a cross-sectional view showing a liquid crystal display device according to the related art. In FIG. 1, a liquid crystal display (LCD) device 1 includes a liquid crystal panel 10, a backlight unit 20, a main frame 30, a top frame 40 and a bottom frame 50.
The liquid crystal panel 10 displaying an image includes first and second substrates 12 and 14 facing and spaced apart from each other and a liquid crystal layer interposed therebetween. The liquid crystal panel 10 further includes first and second polarizing plates 19a and 19b on outer surfaces of the first and second substrates 12 and 14, respectively. The backlight unit 20 is disposed under the liquid crystal panel 10. The backlight unit 20 includes a light emitting diode (LED) assembly 29, a reflecting plate 25, a light guide plate 23 and a plurality of optical sheets 21. The LED assembly 29 is disposed along at least one side of the main frame 30 and the reflecting plate 25 having a white color or a silver color is disposed over the bottom frame 50. In addition, the light guide plate 23 is disposed over the reflecting plate 25 and the plurality of optical sheets 21 are disposed over the light guide plate 23.
The LED assembly 29 disposed on a side of the light guide plate 23 includes a plurality of LEDs 29a emitting a white-colored light and an LED printed circuit board (PCB) 29b where the plurality of LEDs 29a are formed.
The liquid crystal panel 10 and the backlight unit 20 are integrated by combination of the main frame 30, the top frame 40 and the bottom frame 50. The main frame 30 having a rectangular ring shape surrounds an edge portion of the liquid crystal panel 10 and the backlight unit 20. In addition, the top frame 40 covers a front edge portion of the liquid crystal panel 10 and the bottom frame 50 covers a rear surface of the backlight unit 20. Since the top frame 40 has a bent rectangular ring shape whose cross-section has an “L” shape to cover the front edge portion and the side portion of the liquid crystal panel 10, the liquid crystal panel 10 is exposed through the top frame 40 so that the image of the liquid crystal panel 10 can be displayed.
Recently, the LCD device has been used for a monitor of a desktop computer and a wail-mountable television as well as a portable computer, and the application field of the LCD device has been gradually extended. In addition, the LCD device having an enlarged display area with a reduced weight and a reduced volume has been actively researched. However, since the LCD device includes a lot of elements, there is a limit to the thin profile and the light weight of the LCD device.
In addition, the fabrication cost of the LCD device increases due to the top frame 40. After a metal plate is cut to have a rectangular shape, an open portion of a rectangular shape is formed in the cut metal plate. Next, the cut metal plate is worked through bending and drawing processes to have an “L” shaped cross-section, thereby the top frame 40 obtained. Since the top frame 40 is formed to have an open portion by cutting and removing a portion of the metal plate, a material cost increases.
As a result, an LCD device where a width of bezel is minimized without a top frame has been recently suggested. Since the top frame covering the front edge portion of the liquid crystal panel is omitted, the LCD device includes a side supporting means on a side frame for supporting a side portion of the liquid crystal panel. The side frame including the side supporting means may be formed through a double injection molding. Alternatively, the LCD device includes the side supporting means on the main frame for supporting and protecting the side portion of the liquid crystal panel.
The side supporting means has a rectangular ring shape having an opening and is formed of thermoplastic polyurethane or thermoplastic elastomer. After the side supporting means of thermoplastic polyurethane or thermoplastic elastomer is formed on the side frame or the main frame, the liquid crystal panel is disposed on the main frame. When the side supporting means is formed to have a size of the opening exactly the same as a size of the liquid crystal panel, the liquid crystal panel may be bent while the liquid crystal panel is disposed on the main frame. As a result, the liquid crystal panel may be cracked or edge portions of the liquid crystal panel may be broken due to a bending stress. When the side supporting means is formed to have a size of the opening smaller than a size of the liquid crystal panel, the liquid crystal panel may not be supported by the side supporting means. In addition, as time passes after fabrication of the LCD device, foreign substances may be trapped in a gap between the liquid crystal panel and the side supporting means. As a result, an appearance of the LCD device is deteriorated.
The gap between the liquid crystal panel and the side supporting means may be filled with a material such as silicon by a coating process. However, the gap is not be completely filled due to difference in gap distance according to position so that the foreign substances can be trapped in the gap. Further, fabrication cost of the LCD device increases due to the additional coating process and productivity of the LCD device decreases due to increase in fabrication time.